Could a Blood Test Predict Breast Cancer's Return?

THURSDAY, May 15, 2014 (HealthDay News) -- Imagine using a blood test to give you the odds your breast cancer will return. A new German study brings that possibility a step closer.

Researchers have found it may be possible to look for "markers" of cancer cells in routine blood samples and use them to better gauge whether early breast cancer will progress.

The blood test looks for circulating tumor cells (CTCs) in patients with breast cancer. While conclusive data about their relevance has been established for breast cancer that has spread, the CTC test has not been proven to be predictive in early breast cancer, the researchers noted.

It's hoped the CTC blood test will function as a real-time biopsy, providing an early alert system to identify patients who aren't responding to treatment, said lead researcher Dr. Brigitte Rack, senior physician in the department of gynecology and obstetrics at Ludwig-Maximilians University, in Munich.

Besides noting the presence and number of tumor cells in the blood, researchers may be able to study their genetic characteristics, or phenotype, to personalize treatment, Rack said.

"Our data confirms the prognostic relevance of CTCs within a large prospective trial," said Rack. "CTCs could help identify patients with increased risk for relapse who might benefit from additional systemic treatment approaches."

The idea is to prevent spread of the disease "by destroying these minimal residuals," she said.

While the CTC test is commercially available now, the researchers don't recommend its use yet to influence treatment decisions in early breast cancer. "CTC detection in early disease should be limited to patients within clinical trials," said Rack.

For the study, published May 15 in the Journal of the National Cancer Institute, the researchers analyzed the blood of over 2,000 patients after surgery but before chemotherapy, and about 1,500 patients after chemo.

The investigators identified four groups of patients: those who had CTCs before and after treatment; those with no CTCs before or after treatment; those who had CTCs before treatment but not afterwards; and those who only had CTCs after treatment. All participants were followed for about three years.

The results suggest these tumor cells may help predict the spread of breast cancer both before and after chemotherapy, the researchers concluded.

Patients with CTCs in their blood before and after treatment had the shortest disease-free survival time compared to the other three groups.

In general, the chance of being disease-free three years after surgery was lower for those with CTCs than for those without, the results indicated.

Among those who died during the follow-up period, about 41 percent had CTCs in their blood. Of those who survived, only about 21 percent had CTCs.